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Date:   Tue, 13 Sep 2022 16:20:27 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Nathan Huckleberry <nhuck@google.com>
Cc:     Dan Carpenter <error27@gmail.com>, llvm@lists.linux.dev,
        Sandy Huang <hjc@rock-chips.com>,
        Heiko =?iso-8859-1?Q?St=FCbner?= <heiko@sntech.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/rockchip: Fix return type of
 cdn_dp_connector_mode_valid
Message-ID: <YyEQOztVBGl9D3u1@dev-arch.thelio-3990X>
References: <20220913205555.155149-1-nhuck@google.com>
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On Tue, Sep 13, 2022 at 01:55:55PM -0700, Nathan Huckleberry wrote:
> The mode_valid field in drm_connector_helper_funcs is expected to be of
> type:
> enum drm_mode_status (* mode_valid) (struct drm_connector *connector,
> 				     struct drm_display_mode *mode);
> 
> The mismatched return type breaks forward edge kCFI since the underlying
> function definition does not match the function hook definition.
> 
> The return type of cdn_dp_connector_mode_valid should be changed from
> int to enum drm_mode_status.
> 
> Reported-by: Dan Carpenter <error27@gmail.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
> Cc: llvm@lists.linux.dev
> Signed-off-by: Nathan Huckleberry <nhuck@google.com>

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  drivers/gpu/drm/rockchip/cdn-dp-core.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c b/drivers/gpu/drm/rockchip/cdn-dp-core.c
> index c204e9b95c1f..518ee13b1d6f 100644
> --- a/drivers/gpu/drm/rockchip/cdn-dp-core.c
> +++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c
> @@ -283,8 +283,9 @@ static int cdn_dp_connector_get_modes(struct drm_connector *connector)
>  	return ret;
>  }
>  
> -static int cdn_dp_connector_mode_valid(struct drm_connector *connector,
> -				       struct drm_display_mode *mode)
> +static enum drm_mode_status
> +cdn_dp_connector_mode_valid(struct drm_connector *connector,
> +			    struct drm_display_mode *mode)
>  {
>  	struct cdn_dp_device *dp = connector_to_dp(connector);
>  	struct drm_display_info *display_info = &dp->connector.display_info;
> -- 
> 2.37.2.789.g6183377224-goog
> 
>